/* include signal */#include	"unp.h"Sigfunc *signal(int signo, Sigfunc *func){	struct sigaction	act, oact;	act.sa_handler = func;	sigemptyset(&act.sa_mask);	act.sa_flags = 0;	if (signo == SIGALRM) {#ifdef	SA_INTERRUPT		act.sa_flags |= SA_INTERRUPT;	/* SunOS 4.x */#endif	} else {#ifdef	SA_RESTART		act.sa_flags |= SA_RESTART;		/* SVR4, 44BSD */#endif	}	if (sigaction(signo, &act, &oact) < 0)		return(SIG_ERR);	return(oact.sa_handler);}/* end signal */Sigfunc *Signal(int signo, Sigfunc *func)	/* for our signal() function */{	Sigfunc	*sigfunc;	if ( (sigfunc = signal(signo, func)) == SIG_ERR)		err_sys("signal error");	return(sigfunc);}